Method of preparing sheet material



March 10, 1942- J. M. HoTHERsALr. 2,275,438 l METHOD OF PREPARING S-HEETMATERIAL Filed Dec. 3l', 1958 V INV NTOR.

ATTORNEYS gatented-Mar. v10, 1942 METHOD F PREPARING SHEET4 MATERIALJohn M. Hothersall, Brooklyn, N..Y., assignor to American Can Company;New York, N. corporation of New Jersey Application December 341, 193s,serial No. 248,845

4 Claims.

Thepresent invention relates to a method of preparing and securing anarticle onto sheet metal and has particular reference to forming a metalrivet while driving it into an imperforate sheet of metallic material.

The invention contemplates a simple manner oi' joining two pieces ofmetal together in rivet fashion without the need of previously formingthe rivet or preparing the sheet for the rivet and this is done in awaythat permits the use of a rivet member which may be relatively softer,harder or of the same hardness as the piece to which it is attached,such a method utilizing the rivet for forming its own hole or seat inthe sheet material.

One such use of a rivet in sheet material to which it is attached isfound in certaintin or other metalv cans for containing liquid beveragesor food products of various kinds which react electrolytically with themetal of the can and in which a small quantity of a metal which ishigher in the electro-chemical series than the metal of the can andwhich functions as an anodizing agent to off-set any undesirablereactions on the can contents. 'I'his use of a rivet in a container wallwill be illustrated and described by way of example in connection withthe present invention.

f- An object of the invention is the provision of a method of producingand securing a metal rivet in an imperforate sheet of metal wherein themetal from which therivet is formedis forced into the sheet with apressure great enough and in a particular manner to puncture the sheetwhile simultaneously forming the rivet and while securing it in the holeof its own making in a rapid and economical manner which facilitateshigh speed production and accuracy.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accompanying drawing, discloses a preferredembodiment thereof. e

Referring to the drawing:

Figure l is a plan view of a can body blank havinga rivet formed andsecured therein in accordance with the steps of the instant methodinvention;

' Figs. 2 and 3 are sectional views of one form of apparatus forcarrying out the instant method Fig. 4: is an enlarged sectional detailof a portion of the blank and the finished rivet.

As a preferred embodiment of the instant method invention, the vdrawingillustrates-a relatively hard metal -imperforate can body blank Il oftin plate or the like which prior to being formed into can body shape isadaptedto receive a relatively soft metal rivet l2 of aluminum, zinc,magnesium or alloys of these. or similar metals. The rivet is preferablylocated adjacent l an edge of the blank and in position forelectrosteps, Fig. 3 showing the moving parts of the .apparatus in adifferent position to that shown in Fig. 2; and

lytically protecting the metal against corrosion when embodied in thewall of a container filled with a product which would otherwise attackthe metal.

In accordance with the steps cf the instant' method-the blank Il isclamped tightly in a die which confines a portion of the blank and alsoleaves exposed that part of it which is to receive the rivet. While theblank is soclamped a wire il (Figs. 2 and 3) of aluminum, as an example,is fed into position adjacent the conned portion 'of the blank and apellet is cut therefrom4 and deposited on the exposed part of the blank.A pressure is then exerted on the confined pellet and this pressureforces the soft pellet into the relatively hard tinplate, puncturing thelatter with a clean hole I5 into which the soft metal flows, a portionI6 of the blank being completely punched out. At the same time thepellet is reformed into a rivet havinga shank ll (Fig. 4) which ts intothe punctured hole and also having an enlarged flattened head 9 8 whichlies fiat against the surface of the blank.

A hand operated form of apparatus is illustrated in thev drawing forcarrying out the method steps of the invention and includes adie 2|having a. flat recess 22 inits'top surface for receiving the blank il.The die is also formed with a small hole or die' recess 23 which mergesinto a larger clearance hole 2li for the discharge of the scrap portioni6 which is punched out of the blank by the soft rivet.

Clamping of the blank l l in its die recess 22 is eiected by a movableclamp block 2t disposed in a vertical slideway 2l formed in the sidewalls of a housing 2a, preferably mounted on the die 2l. The block isformed with a vertical stem 29 which slides in a bearing 3l formed inthe top of the housing. The upper end of the block stem is engaged by arotatable eccentric clamping member 32 which is carried on a pivot pin33 secured in lugs 34 extended up from the housing 2B. A handle 35 issecuredin the clamping member and by manipulating this handle the posedarea.

The aluminum wire I8 hereinbefore mentioned ls fed into the bore 33 froma supply of the wire which is preferably retained on a spool or reelcarried on a pin or axis-#3l lsecured in a pair of webs L32 which extendout from the housing 2B. The wire is fed by a pair of feed rollers B4mounted on roller shafts d5 carried in the webs 62, the rollers beingmoved in any suitable manner in the proper time for feeding. Theserollers advance the wirethrough a clearance hole il? formed in thehousing side wall and also through a horizontal passageway 45 formed inthe clamping block 26. This passageway communicates with the bore 3B,the end of the wire projecting into the bore at right angles thereto.

The bore 38 also serves as '-a bearing for a plunger 5l which isdisposed above the end-of the wire I4 extending into the bore. The upperend of the plunger is carried in a bearing bore 52 formed in the upperend of the clamping block stem 29. Intermediate its length the plungeris fastened -by a pivot pin 54 to a lever 55 disposed in a slot 56formed in the block stem 29. One

end of the lever is located in a slot orrecess 5l g formed in thehousing side wall and is pivotally mounted or retained in place onapivot pin 58 secured in the housing. The opposite end of the lever isfree and serves as a handle for moving the plunger vertically within itsbearing. This handle also extends through a guide slot 59 formed in theadjacent housing side wall.

When downward pressure is applied to the handle of the lever 55, theplunger 5I moves down in its bore 38 and cuts off the end of thealuminum wire projecting inside the bore. The pellet thus produced movesto the bottom end of the bore Where it comes to rest on the confinedportion of the can body blank ll beneath the bore 38. The plunger movesdown with the pellet and squeezes the latter between it and the blank,

Y as further pressure is built up -by the descending plunger, the pelletbeing confined on all sides can only escape along the line of leastresistance.

This least resistance is by way of that It is thought that the inventionand many of its attendant advantages will ybe understood from theforegoing description, and it will be apparent that various changes maybe made in the steps of the process described and their order ofaccomplishment without departing from the spirit and scope of theinvention or sacrificing all of its material advantages, the processhereinbefore described being merely a preferred embodiment thereof. v

' I claim:

1. A method of producing a soft metal rivet in a relatively hard metalimperforate sheet, which comprises clamping said sheet in a die with aconfined portion of the sheet unsupported, feeding a wire of relativelysoft metal into a position relative to said confined portion of thesheet,

severing a portion of said Wire and simultaneously in the same singlemovement and axially of the severing operation squeezing a portion ofvsaid wire into said sheet, thereby producing a hole in said sheet, vandby said single movement reforming the remaining portion of therelatively soft metal over the hole to produce a headed rivet securedtherein.

2. A method of producing a soft metal rivet in a relatively hard metalimperforate sheet, which comprises clamping said sheet ln a die with aconfined portion of the sheet unsupported, feeding a wire of relativelysoft metal into a position relative to said confined portion of thesheet, severing a portion of said wire to provide a pellet, andsimultaneously in the same movement driving a portion of said relativelysoft metal pellet through said sheet, thereby producing a hole in saidsheet and simultaneously in the same movement upsetting the remainingportion of the relatively soft metal above the hole to produce a rivetsecured therein.

3. A method of producing an aluminumrivet or the like in a sheet of tinplate, which comprises portion of the blank which is unsupported at l1of the rivet. Descent of the plunger 5l ter- Inmates and that portion ofthe peilen which is. left in the bore 38 provides and constitutes thehead i8 of the rivet.

clamping said'sheet in a die with a confined portion of the sheetunsupported, feeding a wire of aluminum into position above saidconfined portion of the sheet, cutting off a pellet from the aluminumwire and punching said pellet into said 'sheet in a single operation,thereby producing a hole in the sheet and simultaneously reorming saidpellet into a rivet which fills said ole.

4. A method of producing and securing a metal rivet in an imperforatesheet, which comprises clamping the sheet between upper and -lowerunyielding surfaces, said upper surface having an opening and said lowersurface having a smaller axially aligned opening forming an unsupportedsection for the sheet at the lower side, positioning an elongated pelletof metal transversely of said upper opening, and then in a singlemovement compressing said pellet while confining it against unduelateral spreading to force the metal through the clamped metal sheet atits unsupported section, thereby forming a. rivet and se-

